Isabelli Fontana, the new face of Mango. waering a piece from the autumn/winter 2011 collection. Photo: MANGO

When Kate Moss speaks, people listen. It's not just that she is a living icon, perhaps the most famous British woman on the planet bar the Queen and the Duchess of Cambridge. It is that, in a world where celebrity self-promotion is king, she chooses to speak so rarely.

She is the most super of the supermodels; her face has sold billions of frocks and perfumes and handbags across the globe and yet you cannot put a voice to it. To pass up the chance to interview her would be like turning down an opportunity to discuss the whereabouts of Lord Lucan with Elvis Presley while riding on the back of Shergar.

"You can't tell anyone," says my boss, "but it's something to do with Mango". I call the PR woman at Mango, a high street fashion store which started in Spain. She, too, tells me I can't tell anyone. I ask what Miss Moss is doing with the company; perhaps a collaboration similar to the one she did with Topshop? "Well that's the thing," says the PR woman. "We don't really know." I ring off with the curious knowledge that I am not allowed to tell anyone about something I don't know.

Here is what we
do
know about Kate Moss: she is 37, from Croydon, and was spotted at JFK airport when she was just 14 years old. She started the whole waif look, and ended up missing school at 16 because she got so drunk on whisky after a John Galliano show in Paris. She bathed in champagne with Johnny Depp, had alleged threesomes with Jude Law and Sadie Frost, and got caught snorting cocaine with her then lover Pete Doherty.

In between, she had a daughter, now 8, with magazine journalist Jefferson Hack, and is about to get married to Jamie Hince, who is a musician and - in common with all her boyfriends - looks a bit grubby. Some people believe she never gives interviews because her sarf London accent spoils the effect of her fabulous face. Another theory is that she simply has nothing to say, or that everything she has to say is so outrageous and decadent it simply cannot be said. Thus, the quotable Kate Moss is short and mostly inane, including such gems as "I'm passionate about clothes" and "I'm sure there are [photos she wishes hadn't been taken of her] but I can't think of one right now". The last time they let her speak she repeated the dim observation that "nothing tastes as good as skinny feels".

Whatever the case for Moss's silence, it has turned her in to a riddle wrapped in an enigma inside an Hermes bag. We are to meet in the Ritz in Paris - the glamour of Croydon's Whitgift Centre, where she surprised residents with a rare return visit earlier this week having landed on the roof in a helicopter to film an advert for Rimmel, far behind her. Our interview, I have been told, will come with restrictions. Of course it will. I will have only 20 minutes with her, and I will have to share those 20 minutes with two other journalists, from Turkey and Portugal. I will not be able to ask about her forthcoming wedding, her daughter, or her private life, and I will have to send all my questions over for her to approve.

This is a shame. She must have some tales to tell; a reporter who snuck into her 30th birthday claimed it appeared to have turned into an orgy. Still, I send over some questions about style tips and fashion - 20 minutes with Kate Moss is better than none at all. The questions come back. She doesn't want to talk about where she will be in ten years' time, or how she feels about the prospect of turning 40. I sit on the Eurostar chewing my nails.

I have bought her some presents in the hope she might warm to me: a packet of fags, and some jam (apparently, she loves jam). I arrive at the Ritz and am told that Kate is running late - "she is having 'er make-up done," as the harassed looking PR girl puts it. I am led to the world's most glamorous holding pen - a suite overlooking the gardens - and wait with journalists from as far a field as Russia, America and China, who have travelled all this way in the hope of hearing Kate Moss speak. "Fifteen hours is my flight!" says one glamorous woman, neatly pointing out how big a star the girl from Croydon has become.

We are told she is going to be 30 minutes late. Half an hour passes and there is no sight of her. People twiddle with phones. A waiter hovers with tea and chocolates. Nobody touches them. "She should be here in five miniutes," says the PR girl. Those five minutes tick by agonisingly slowly. A couple of us go for a turn around the garden. "I am getting very nervous now," says the journalist from Portugal. Manicured nails drum on marble surfaces.

And then, the unmistakeable shrieks of a south Londoner echo around the Ritz lobby outside. Kate Moss walks through the door, all Brigitte Bardot hair and skinny jeans and blazer and t-shirt. "Hello!" she beams. "I'm Kate!" She's Kate! I am standing in front of Kate! And her voice… well, it's much
huskier
than I had expected, with shades of Mariella Frostrup.

I give her my presents. I am scared. There are eleven effortlessly cool fashionistas in the room and then me, handing her some… "jam! I love my jam. I've just had a batch of it come through, I've been making it," Kate Moss makes jam? Now that
is
interesting.

The Turkish girl and the Portugese woman ask their questions first. "I'm doing a commercial for Mango with Terry Richardson," Kate explains. Is she wearing Mango? "Yeah". Did she choose the clothes she wears in the commercial? "Yeah". Does she know any Turkish people? "Yeah," she says, looking a bit bemused. "But you know, I haven't spent that much time in Turkey…"

Does she think she's an icon? "No! Liz Taylor's an icon. I'm just normal." What goals hasn't she achieved? "Well I wasn't in [George Michael's] Freedom video… I just missed it. That would have been amazing."

And then it is my turn. I take a deep breath. What does she think of the other famous Kate, the Duchess of Cambridge? "Oh I love her! She was so chic and
seamless
. And just beautiful, it was just as a royal wedding should be." Where did she watch it? "In the country, with loads of friends and kids who were all crying. There were tears. We were like "ok, you can marry Harry!" Might she one day be Prince Harry's
mother-in-law
then? "Nah! No!"

Would she like to be made a Dame for her services to the fashion industry? "Ha ha. Can you imagine? I'm too young to be made a Dame. A Dame's for old women. Like Margaret Thatcher." I say she's a Baroness. "I'd prefer to be a baroness. I'd quite like to be Lady Kate. But I'm happy just as I am."

And that is that. My time with Kate is over. "Thanks for the jam!" she beams as I head out of the door. As I leave I remember a question the Turkish journalist asked: what's her favourite bit of her body? Her eyes? She thought for a bit. "My mouth, I think that's what other people would say." And I'd agree. I just wish she's use it a bit more.